E1M3: Research Complex (Double Impact)

E1M3: Research Complex is the third map of Double Impact. It was designed by Matt Cibulas (RottKing) and Ralph Vickers (Ralphis), and uses the music track "Sinister" by Robert Prince. The par time defined in the DMAPINFO lump of the edition released as official add-on is 21:00.

Normal exit
Open the door on your right and shoot the enemies ahead, which will alert more monsters to your left and right, then head east to a UAC door and open it to enter a corridor with steps on either side. Head up the south steps to a tan passage and follow it to a switch that you can flip to lower a floor behind you, drop down to that floor then head south to a dark storage room containing imps and zombiemen. Open the door on the west side of the room (it has a spectre waiting in front of it) and follow a corridor south to a room with computer columns, then head straight forward and press a recessed button at the other end of the room to lower a lift to the south; approaching it will lower the columns and release lost souls. Get on the lift, which is brightly lit to help you locate it, and go up to the ledge above then head and north to find some imps guarding the yellow keycard. Make sure you flip the switch in the nearby recess to re-open the door to the computer column room, as it has closed behind you.

Go back to the starting point and head north to see a small building surrounded by an inescapable nukage pit - the normal exit is inside this building. Head through the west door then proceed north to see a blue key door along with a doorway to your left. Step through the doorway to enter a chamber with imps and zombiemen, then go through either of the doorways on the west side to find a switch next to a locked door; flip the switch and quickly kill the enemies that are released behind you, then return to the previous chamber to find that the exits have sealed and the columns have lowered to reveal the red keycard along with two cacodemons (plus lost souls on Hurt Me Plenty (HMP) skill level or higher). With the red key, go back to the locked door and open it to confront imps guarding a button that will re-open the bars and allow you to leave. Go through the south doorway then turn right to see another door, open it then go up some steps and turn left at the top to enter a small room with another button. Press the button then go back to the nukage pit to find that a bridge has risen from it - do not cross yet, as the exit door on the other side is still sealed.

Go through the door on the east side of the exit area to enter a hall with a green building surrounded by nukage, then fight your way to the east side and go up the steps to a tan walkway. Go to the end of the walkway to find a switch and pull it to raise a bridge across the hall, head across then go up the steps in front of you and turn left to see a red key door. Go through the door to enter a room with a cross-shaped block then head up the steps on the south side to find a button; pressing it will open the exit door, but will also lower the cross-shaped block to reveal imps, shotgun guys, zombiemen and a demon. Fight your way back to the exit area and cross the bridge, then flip the switch on the other side to go to.

Secret exit
After getting the red and yellow keys, follow the directions below for secret #5 to enter a hallway with two locked doors. Open both doors using the keys and press the buttons behind them, then open the east door and head across a bridge to reach a T-junction. Turn right and go round the corner to confront a spectre guarding a door, head through it and follow a passage past some zombies, imps and a lost soul to get to another door. Open this door and turn left to go through a doorway protected by a demon, then follow a ledge south around a nukage pit to reach a fenced area where some imps are protecting a switch. Flip the switch to raise a bridge on the other side of the nukage, then head across that bridge and open the door here to get outside where a crowd of enemies are waiting - from this point you cannot go back without the blue key.

Head south through the next door and open it to find a group of imps blocking your path, go through to a room with two staircases then head up either staircase to find zombies and imps guarding a green door. Go through this door and head straight forward to collect the blue keycard; taking it will lower the floor and reveal three doorways blocked by imps. Fight your way out of the trap then go through the south doorway and turn right to see a switch next to a radiation shielding suit; take this item and flip the switch then follow the hallway north through an open door to enter a narrow nukage trench. Follow the trench west and north, noting one or two spectres that are released behind you, then open the metal wall at the end of the trench to return to the bridge area. Head east until you see a lift on your left that you can activate to climb out of the pit.

Go back to the normal exit area and pass through either of the doorways on the north side to find a blue key door, open it then go down the steps in front of you to enter a seemingly empty room (bars will close behind you to block your escape). Arm yourself then walk towards the computer screens in the center of the room, which will open five closets around you containing imps, zombies, demons and one or two cacodemons. Slay them all then enter either of the north closets and press the button in the passage between them, which will open the exit door on the east side of the room. Go through this door and approach the button in front of you; the floor will lower and take you down to an imp guarding the actual exit button, which leads to.

Other points of interest
Search the middle of the dark cargo room to get a chainsaw.

Enter the room west of the normal exit, then activate the lift on the south side of the block in this room and ride it up to get a chaingun.

Secrets

 * 1) Along the way to the yellow key, you will be in a dark cargo room. The walls in this room are covered with vines, but you can go through the vines at the southern end of the room, There are rockets, an armor and a medikit here. An imp will also be present on HMP or higher. (sector 123)
 * 2) The room just after the dark cargo room has a section of tech wall that is different than the rest. Open this wall for clips, shells and armor bonuses, and flip the switch for a lift to another room with rockets and a shortcut back. (sector 240)
 * 3) At the room east of the normal exit, there is a switch in the south-west corner that raises a bridge. At the middle of this bridge is a door. To open it, go into the nukage at the southern end of the building and find the switch on the wall. Then lower the bridge and ride it up. Inside this room is a berserk pack, armor bonuses and ammo. Some zombiemen may also be inside. (sector 190)
 * 4) Near the switch that opens the normal exit door, look along the hallway to spot one of the walls being in between two metal ridges. Open this wall for a secret hallway where you can get, among other things, a partial invisibility and a rocket launcher. The hallway takes you back to the normal exit room. (sector 752)
 * 5) Open the door at the start and head east and open the door here. The next door you see cannot be opened directly. Instead, climb the steps up to a hall with four doors. Open either green door, and on the wall, you can faintly spot a red button, which will open up the door that you could not open before. This will lead to the southern-most section of the map, but you will need both the red and yellow keys to proceed. (sector 363)
 * 6) Enter secret #5 after getting the red and yellow keys, then open the doors and hit the switches in both side rooms. Open the east door and walk across the bridge, then open the next wall you see to find a backpack and two stimpacks. (sector 390)
 * 7) At the southern portion of the map leading to the blue key, go to the place with the switch that raises the bridge, then open the green wall east of that switch. Get the rockets here and open the door to get health bonuses and a medikit while fending off zombiemen. (sector 513)
 * 8) Once you find the blue key, backtrack all the way to the western section of the map and open the blue door. The teleporter in this room takes you outside where you can collect a supercharge. (sector 347)

Bugs
There are three points of no return that block the way back and force the player to move forward, all of which can be backed out of to softlock the map. There are side routes that open for multiplayer access, but those can fail as their triggers are only reached after the main route is blocked.
 * The blue key path involves raising a bridge, which will lower after it has been crossed. Backing down after making it lower will softlock the map.
 * Immediately after crossing the bridge, there is a door leading to a walkway with enemies. If a player peeks ahead but not far enough to hit the multiplayer access trigger and backs off, the floor will crush the player against the ceiling, and block the way forward with no way to progress in multiplayer. This crusher likely also immobilizes the player instead of killing them.
 * The stairs leading down to the exit room will attempt to trap the player with bars. The player can back off and get softlocked. Multiplayer access is not triggered until reaching the middle of the room.

Current records
The records for the map at the Doom Speed Demo Archive are:

The data was last verified in its entirety on December 9, 2021.

Player spawns
This level contains seventeen spawn points:
 * 1) facing south. (thing 813)
 * 2) facing south. (thing 814)
 * 3) facing south. (thing 815)
 * 4) facing north-west. (thing 816)
 * 5) facing east. (thing 817)
 * 6) facing south-east. (thing 818)
 * 7) facing north. (thing 819)
 * 8) facing south. (thing 820)
 * 9) facing east. (thing 821)
 * 10) facing north. (thing 822)
 * 11) facing north. (thing 823)
 * 12) facing south. (thing 824)
 * 13) facing west. (thing 825)
 * 14) facing south-west. (thing 826)
 * 15) facing north. (thing 827)
 * 16) facing east. (thing 828)
 * 17) facing north. (thing 829)

Things
This level contains the following numbers of things per skill level:

Trivia

 * Several areas of this level bear a loose resemblance to areas from Knee-Deep in the Dead:
 * The starting area and the room west of the normal exit area are shaped like the starting area and center room from respectively.
 * The normal exit area, with its bridge over inescapable nukage, resembles the starting area from.
 * The secret exit room resembles the end of.